The United States, Canada and Mexico vowed today to fight what they called unjustified bans on pork products in the wake of a H1N1 flu outbreak that started in Mexico, according to Reuters. Around 20 countries -- most notably Russia and China -- have imposed widespread import restrictions on pork and pork products from major U.S., Canadian and Mexican agricultural regions, amid fears over the disease, originally called swine flu. In a joint statement, the three NAFTA nations called for an end to "unscientific bans on pork imports" over the outbreak. "We urge our trading partners to remove these restrictions on our products immediately. We will continue to follow this situation closely, and will take any steps to prevent the enforcement of unjustified measures against our exports, as appropriate," the NAFTA partners said. This comment most likely refers to a possible challenge at the World Trade Organization, which can often be a long, drawn out process. Global trade in pork is worth about $26 billion a year. Leading exporters include the three NAFTA nations as well as the European Union and Brazil.